SON is an abbreviation for Self-Organizing Network. The idea behind SON is to minimize the load for the operator of the network by dynamically adding functions, such as self-configuration, self-optimization and self-healing. A SON function may refer to an autonomous activity which is a process which is fully controlled by a machine without requiring human interaction. Furthermore, a SON function may refer to an automatic activity that is a process where a significant part of the action is handled by a machine, but where some human interaction is required, e.g. where an operator is required to activate machine specific macros or required to verify results.
There is a trend to add these functions in network elements, e.g. RBS (Radio Base Station). In current networks there is a lack of SON functions related to inventory management. In particular, there is no autonomous way allowing self-inventory management of indoor antennas.
A further aspect of indoor cellular networks is the need to determine the exact position of a mobile device used in the indoor cellular network. By way of example, in case of an emergency call of a mobile device used in an indoor cellular network, the exact position of the mobile device is needed. With current location methods it is not possible to exactly determine the position or location of a user with a mobile device. The precision of the methods known in the art are not enough to determine the exact position of a mobile device. By way of example, it is possible to roughly determine the position of a mobile device using the cell ID. However, the cell ID is not suited for indoor use and has a precision of about 200 to 500 meters. When taking into account the angle of arrival of the signals from the mobile device, the position of a mobile device can also be determined. However, the precision with 100 to 500 meters is not enough and the angle of arrival method is not suited for indoor use. Another possibility for locating a mobile device is the RTT (Round Trip Time) location method. Both the cell ID and the distance from the base station are used to calculate the position of the mobile device. As in the above discussed methods the precision of this method with 150 to 400 m is not high enough and it is not suited for indoor use. The use of the uplink U-TDOA (Time Difference of Arrival) has a precision of less than 50 meters and may be used indoors. However, the precision is not high enough for an exact location determination. The use of satellite based position methods, such as GPS, provides the required precision, however, the GPS signals can normally not be received indoors.